This past summer was one of the hottest in recent memory in usually temperate San Diego, California. Multiple heat waves succeeded one another on a week-to-week basis, and the sun seemed more brutal than usual. I remember a recent heat wave (before the current one; there’s a heat advisory in effect as I write this) that started on a Tuesday afternoon: As I was carrying some things out to one of my cars, it was getting hotter, not cooler, as the sun moved toward the horizon. The hot, dry heat was aided by arid winds from the east, and I remember feeling particularly relieved as I got into my idling car, which had an ice-cold interior thanks to the fully operational A/C system. It didn’t take longer than a few minutes of sitting for the cabin to cool down, and my satisfaction was palpable as I sank into the plush leather seat and buckled my seatbelt.
Right now all three of my cars (two BMWs and big-body Lexus) have functioning A/C, but none of them freeze my face off like my 1985 BMW 325e coupe. It’s incredible; nearly everything else is falling apart on the car, but the air-conditioning has been blowing cold ever since I gave it some attention during the summer of 2019.
When I say attention, I need to issue something of a disclaimer. This is BimmerLife, after all, the home of Rob Seigel, the Hack Mechanic, who happens to have written a book about this very subject, Just Needs a Recharge: The Hack Mechanic Guide to Vintage Air Conditioning. If you want to learn the right way to go about giving your older BMW cold air-conditioning, read his book. If you want to know what I did last summer, which has been working for well over a year now, through multiple periods of inactivity and storage and incredible heat, without so much as breaking a sweat (well, a particular line under the hood definitely sweats, but you know what I mean), then read on.
To give a bit of background, I’ve had the A/C fail on a number of different cars I’ve owned over the years. On one particular 1986 535i I owned many moons ago, the system failed during the car’s first winter in northern Arizona, which was actually less convenient than it sounds, since the region can still get quite hot during the off season. Upon returning to San Diego, I bought an R134a recharge and conversion kit from NAPA, shot the can (which may or may not have contained some kind of sealant) into the system through the screw-in adapter fittings, and had cold A/C for the next few months until I sold the car.
It worked great, and I was satisfied. Was it optimal? Probably not—but hey, it worked.
The next vehicle I owned which experienced A/C failure was my Audi B6 S4. I’m not sure who designed this particular Audi, but I detest them to this day, not least for the horrendously complex engine which burned oil at a rate I’ve never experienced before or since. But my ire is mostly focused on the air-conditioning: The compressor wasn’t belt-driven, but geared off the engine’s crankshaft—no, I’m not kidding. To make matters worse, the compressor failed right after Audi had replaced that oil-burning 40-valve V8, and that was the last straw. I traded the car, with non-functional A/C, for a certain Techno Violet E36 M3.
The final car (aside from the E30) that had failed air-conditioning during my ownership was a hand-me-down 2007 Honda Civic. I hastily bought a can of R134a to recharge the system, since the A/C had experienced weak performance for years, but before I emptied its contents into the lines, I did something I always do: research. I found that this particular eighth-generation Honda Civic would rather commonly lose its air-conditioning not due to a failure with the system itself, but due to an electrical malfunction. The problem seemed to be the relay responsible for engaging and disengaging the compressor. You know the one; you hear it click every time you press the snowflake button.
I replaced the relay, and within minutes of starting the engine, I felt cold air exiting the cabin vents. Aren’t those repairs the best? Something may very well have been going bad within the A/C compressor’s clutch, but it worked for the remainder of my ownership.
Getting back to the E30: Being editor of BimmerLife and a long-term reader of Roundel, I’ve been following the chronicles of Rob Seigel for a long time, and was always interested in his air-conditioning-related stories. Whether he was talking about how to fit a particular compressor, which oil to lubricate it with, and which refrigerant to use, the stories tended to intrigue me, since I consider cold A/C rather necessary. But my E30 is something of a beater project, so even though I went through the motions of pricing out a full system replacement with all new components, including a snazzy parallel-flow condenser and a new Sanden compressor, I knew that I was unlikely to ever go down this path.
When it came time to look at oils and refrigerants, I began to get excited. The reason was simple: I had found what I believed to be a game-changer. Instead of converting the system to run the modern but less than optimally efficient R134a, or scouring my local network for new-old-stock cans of R12, I put together my own recharge kit of a new-to-me kind of refrigerant: R12a. It has been around for a while now, but I was attracted to it for one reason above a handful of others. Billed as an R134a replacement that allows systems to run more efficiently and with less pressure, the molecule for R12a is physically larger than that of R134A and R12. This means that it requires a larger orifice through which to leak, and I was certain that the original system in my 325e had plenty of emergency exits.
Other benefits include a requirement for less refrigerant (part of R12a working more efficiently) and the fact that R12a has an atmospheric lifetime measured at a fraction of the original R12. R12a is also considered an HCFC, while R134a is an HFC, and the original freeze-your-face R12 is a dreaded CFC. There’s a major downside with R12a though, and that is its flammability. So why give it a try? Well, I didn’t actually use R12a, but the closest legal and permissible alternative, which a number of companies market as an R134a replacement. I have to assume this stuff is still highly flammable, but its efficiency over other refrigerants means you don’t need as much to power your system (not that it matters much, as any flammable gas under high pressure still represents a danger). It also contaminates the system in which it used, meaning you should really start with a clean slate if you want to switch to another refrigerant. This wasn’t much of a worry on the estimated 300,000-mile, $1,400 E30 325e in question, which is on its original and previously inoperative air-conditioning system.
I don’t own a set of A/C pressure gauges, and although the set at Harbor Freight is tempting, I’ve never bitten the bullet. To test whether the system in my E30 still had pressure, I employed a single-use test-tip tool which releases a bit of the system’s pressure into a sort of visual catch can which has some material for the oil to contrast with. If I remember correctly, the system had zero pressure, and this was after I had replaced the faulty A/C button with one that would actually stay depressed, and had driven around with the compressor (and condenser fan) running. This wasn’t a surprise, as I assumed that the car had not had functioning A/C for a long time. It also wasn’t a problem, because it meant that I didn’t have to worry about evacuating the system of whatever was left in it.
Using a hose I either ordered or had from a previous A/C adventure, I shot a single can of Enviro-Safe R134a replacement into the system, and before the can had finished emptying itself into the appropriate line, cold air was already leaving the vents inside. My initial reaction was joy, but it remained tempered, as I knew that this was likely to last only so long—whether that period of time was a few minutes, a few hours, a few days, weeks, or months.
To be completely honest, I’ve been avoiding writing this story because I don’t want to jinx it. But as I sit here writing this column, it’s been nearly sixteen minutes since I shot that single can (remember, you don’t need as much R134a replacement) of refrigerant into my dilapidated old eta, and the system is still blowing cold air—so cold, in fact, that I am fairly certain my E30 now has the strongest air-conditioning of my three cars. It may be because I simply set the E30’s climate controls to max cold and leave them there, as opposed to my other cars, in which I actually dial in a temperature setting using the automatic HVAC. (I know that the E30 also has a decently accurate HVAC system which can hit the temp prescribed by the knob, but I’ve always set it to max and let it run.
I’ve driven my E30 on some of the hottest and most humid days and nights, and put the system to the test during a few of this year’s heat waves. It hasn’t failed. The 35-year-old Bosch compressor keeps on going, and the corroded condenser manages to perform its function. I have long been a leave-the-A/C-on-all-the-time kind of guy (perhaps I owe the habit to living in a coastal microclimate, and wanting to avoid letting the windows fog up), but I’ve adapted the same practice to my E30. I just leave that blue snowflake button depressed in the on position, and bask in its wondrous glow.—Alex Tock
[Photos courtesy Alex Tock, BMW AG.]